The present invention relates to a strainer structure for aquarium, and particularly to a strainer having an air pump that may form bubbles by air pumped in the water for diffusion to increase oxygen solubility in the water when the aquarium is pumping air, for improving water quality and water circulation.
Generally speaking, an aquarium has a strainer which provides oxygen solution by pumping air and is beneficial to biological attachment so as to supply adequate oxygen content and suitable water quality for survival. A known type of biological strainer for an aquarium is shown as FIG. 1, comprising an oxygen solution tube 11 and an intake tube 12 at a proper height on said oxygen solution tube 11. Said oxygen solution tube 11 is set in the end of a connection body 13 corresponding to a drain hole 131. The external side of connection body 13 has a sponge 14. Said oxygen solution tube 11 and intake tube 12 are directly set together, so poor tightness exists on the seam 120, and on the end of connection body 13 at a circular setting slot 132 for oxygen solution tube 11 to set in. Drain hole 131 penetrates through the inlet hole 133 in connection body 13. When air is driven into the oxygen solution tube 11 by virtue of intake tube 12 suction against drain hole 131, and because the sponge 14 can allow water to infiltrate, causes water to flow into drain hole 131 by virtue of intake hole 133, enabling oxygen solution tube 11 to fill with water for producing oxygen solution with air driven from intake tube 12. However, it has following defects:
1. Referring to FIG. 1, when air is directly driven into the water by virtue of inlet tube 12, it is supplied through a single outlet tube so bubbles 15 formed by air in water are large, whereby oxygen gas in the bubbles 15 could hardly be soluble in water, i.e. bubble floating and escaping from water so that oxygen solution is not good.
2. The lash between said sponge 14 and connection body 13 is beneficial for attachment of water animals. However, because of a small lash, it may only provide a very small space for water animals to attach.
3. The seam 120 between oxygen solution tube 11 and intake tube 12 has poor tightness.